Send emails through Mailgun SMTP on CentOS 7
Install the dependencies:
$ yum install postfix cyrus-sasl-plain cyrus-sasl-md5 mailx -y
In /etc/postfix/main.cf, append the following to the end of file:
relayhost = smtp.mailgun.org
smtp_sasl_auth_enable = yes
smtp_sasl_password_maps = hash:/etc/postfix/sasl_passwd
smtp_sasl_security_options = noanonymous
smtp_sasl_tls_security_options = noanonymous
smtp_sasl_mechanism_filter = AUTH LOGIN
Run the following to configure the authentication details:
$ echo 'smtp.mailgun.org postmaster@<mailgun_host>:<mailgun_credentials>' > /etc/postfix/sasl_passwd
$ chmod 600 /etc/postfix/sasl_passwd
$ postmap /etc/postfix/sasl_passwd
$ systemctl restart postfix
And finally test it out!
$ mail -s "Test mail" your_email@example.com <<< "A test message using Mailgun"
$ cat /var/log/maillog